An invoice is a commercial document, issued by a merchant to a customer in a sales transaction, typically indicating a product sold or service rendered, a quantity, an agreed transaction amount for the product or service, and payment terms that specify, among other things, when payment is due. Invoices are beneficial to a merchant's business as they provide financial flexibility for customers (i.e., delayed payments), thereby incentivizing the customers to engage in transactions with the merchant. However, unpaid invoices, which inherently represent unrealized income for the merchant, are recorded as financial liabilities (e.g., account payables). Accordingly, the sooner an invoice is paid, the more financially healthy is the business.